Faulting of stratigraphic subterranean formations creates hydrocarbon traps and flow channels. As a result, accurate identification of the fault curves and fault surfaces is essential to the interpretation of most seismic data volumes. Those persons involved in exploration to locate such hydrocarbon traps and flow channels in the formations use an interactive workstation on which is displayed sections of seismic data. The seismic data includes a plurality of fault curves or fault cuts, each fault cut representing the intersection of a fault surface with a horizontal "horizon" inherent in the seismic data. However, when using most existing workstation tools that include interactive computer programs, the interpretation of fault cuts on horizons in the seismic data is tedious and time consuming; that is, the workstation operator must view the seismic data volume on the workstation display, manually determine by viewing the seismic data where a plurality of horizons are located in the seismic data, and manually determine by viewing the plurality of horizons where a plurality of fault cuts are located in each of the plurality of horizons in the seismic data volume. For a particular vertical section, the workstation operator must carefully move a cursor over the entire length of an observed fault curve, pausing to click at points along the curve enough times so that connecting the points by straight line segments satisfactorily represents the entire curve. Then, this process must be repeated for each section on which the fault curve is desired, perhaps hundreds of sections. In map view, the intersection points of the fault curve and the horizon create a pair of points, called fault contact points. These points must be connected to render the trace of the fault. This manual method for determining the fault cuts in the horizons on the seismic data, aside from being very tedious and time consuming, produced an inconsistent set of results in terms of accuracy because the accuracy of the results depended upon the mental awareness of the workstation operator.
To automate this process various approaches have been proposed. For example, one such method and apparatus for automatically determining where a plurality of faults are located in the plurality of horizons in seismic data, is disclosed in U.S. Pat. No. 5,537,320 to Simpson et al. In the Simpson et al patent, a seed fault is placed by a user in the seismic data, and a plurality of fault curves are determined, by a computer program executing in a workstation, in response to the seed fault placed by the user in the seismic data. The Simpson patent does not teach using the technique and apparatus for automatically determining where a plurality of horizons are located in seismic data.
Therefore, there is a need in the prior art for a more accurate method and apparatus adapted to be disposed in a computer workstation for automatically identifying fault cuts and horizons in seismic data from an input seismic data volume that contains a plurality of horizons and faults, in particular, an accurate method to connect fault contact points between adjacent seismic lines, where one or more fault cuts and horizons are located in the seismic data. In addition, there is also a need for a more accurate method and apparatus for identifying fault cuts and horizons in seismic data that gives the user finer control over the parameters used by the computer workstation and program operating therein to automatically identify fault cuts and horizons.